Manual emergency control is based on the analysis of real-time operating conditions of power systems and its control commands are issued by system operators， which can play a key role in the timely elimination of the system emergent， but it should be implemented by combining the concept of emergency control based on detection of insecure phenomena with the real-time decision support technology using wide area measurement system（WAMS） and energy management system（EMS） information. A coordinated preventive roadmap using manual and automatic emergency control is presented， including identification of both the feasibility and applicability conditions of manual emergency control， decision support based on measurement as well as simulation and ability of maintaining overall situational awareness. Design ideas of decision support technology by integrating real-time measurement and simulation analysis are exemplified by using low-frequency oscillation， voltage stability and cascading outages.